Ettercap

Ettercap is an open-source suite for man-in-the-middle testing, packet inspection, protocol dissection, and network discovery. It best suits security professionals, network engineers, and researchers who are comfortable with command-line or source-built tools. Its breadth and payload-filtering capability are compelling, but platform and build requirements make it a poor fit for users seeking a turnkey desktop analyzer.

Overview

Ettercap combines live connection sniffing, active and passive protocol dissection, traffic filtering, and host analysis in one toolkit. You can run it through a graphical interface, a command-line interface, or an ncurses interface, so it accommodates both terminal-focused workflows and users who prefer a visual front end. The project is community run and 100% open source under the GPL-2.0 license, with development and bug reporting handled through GitHub.

Its focus is testing and analysis rather than general-purpose traffic visualization. Ettercap can inspect traffic, alter packet payloads through compiled filters, and infer network details from observed LAN traffic. That combination is useful for controlled assessments and troubleshooting, provided you understand the legal and operational risks of man-in-the-middle work.

Key features

Traffic capture and protocol analysis

Ettercap supports both active and passive dissection across many protocols, with PCAP support, flow analysis, traffic decryption, and remote capture. In practice, that gives analysts several ways to examine sessions and reconstruct what is happening on a network instead of relying on a single capture mode.

Filtering and payload changes

The integrated filtering engine is a major differentiator. Users can write rules that modify packet payloads, then compile those rules with etterfilter. This is powerful for test scenarios and protocol experimentation, but it also demands careful rule authoring and a clear understanding of the traffic being changed.

Passive network discovery

By observing LAN traffic, Ettercap can extract host, operating-system, port, and gateway information. That makes it useful for building an inventory during an assessment without requiring a separate discovery utility, although the results depend on what traffic is visible.

Multiple interfaces and current release

Command-line, graphical, and ncurses interfaces let teams fit Ettercap into scripts, terminals, or desktop sessions. The latest listed release is 0.8.4.1-Garofalo, released April 7, 2026. Its downloads page provides SHA256 checksums for bundled-library and source-only archives, and this release fixes a heap-out-of-bounds read in etterfilter identified as CVE-2026-3606.

Pricing

There is no paid tier, usage quota, seat charge, or free-trial period. The free plan is the complete open-source project, making it suitable for individuals, labs, and organizations that can manage deployment and maintenance themselves. The trade-off is not a feature cap but the operational work associated with building, configuring, and supporting the software.

Platforms

Ettercap supports Linux, macOS, and self-hosted deployments. The project lists Debian/Ubuntu, Fedora, Gentoo, Pentoo, Mac OS X, FreeBSD, OpenBSD, and NetBSD among tested systems. Windows Vista, Windows 7, Windows 8, and Windows 10 are identified as unsupported distributions; installation may work with additional settings, but Windows is not a dependable target for a standard deployment.

Source compilation requires libpcap, libnet, pthread, zlib, CMake, Flex, and Bison. That dependency list favors administrators who already maintain development environments over users expecting a one-click installer.

Who it's for

Choose Ettercap for authorized network testing, protocol research, host and LAN analysis, or training environments where packet manipulation is part of the exercise. Its CLI, remote-capture, and filtering capabilities also suit automation and repeatable lab work. Look elsewhere if you need broad desktop operating-system coverage, a managed service, or an interface that hides build and network-configuration complexity.

Pros and cons

• Pros: Broad capture, decryption, flow-analysis, and protocol-dissection functions in one open-source suite.
• Pros: Payload-modifying filters can be compiled with etterfilter for controlled testing.
• Pros: Passive discovery can reveal hosts, operating systems, ports, and gateways from observed traffic.
• Pros: CLI, graphical, and ncurses interfaces support different working styles.
• Cons: Windows is an unsupported target, limiting its practicality for Windows-first teams.
• Cons: Source builds require a substantial tool and library chain, adding setup effort.
• Cons: Man-in-the-middle functionality is specialized and inappropriate for routine, non-testing traffic monitoring.

Alternatives

For a broad directory of comparable tools, see Network Protocol Analyzers.

Scapy is a free, GPLv2 Python-based option spanning API, Linux, macOS, self-hosted, web, and Windows environments; choose it when programmable packet construction is more important than Ettercap's multi-interface suite.

termshark is a free, MIT-licensed terminal analyzer for Android, Linux, macOS, and Windows that requires tshark 1.10.2 or newer; it is the better fit for a focused terminal workflow.

NETCAP offers a free Core edition with 66+ audit record types and a paid Pro plan at $548 a month; consider it when audit-oriented records and a web-capable deployment matter more than packet-payload filtering.

NetworkMiner provides a free edition and GPLv2 open-source managed C# code; it suits users who want a .NET-based alternative.

PacketSnitch is a paid product with a free plan and free trial.

Arkime is free, open source, self-hosted, and web-facing with no paid-only features or license fees.

Kismet is free and open source across API, Linux, macOS, self-hosted, and Windows, with no paid plan or stated usage limit.

OpenGrep is a free, open-source CLI static-analysis engine rather than a direct traffic-analysis replacement.

Verdict

Ettercap is a strong choice for security practitioners who need open-source man-in-the-middle testing, payload filters, protocol analysis, and passive network discovery across Linux, macOS, or self-hosted systems. Choose it for breadth and control; look elsewhere if unsupported Windows targets or source-build complexity outweigh the value of its specialized testing toolkit.